gpu: Add GpuFence framework.

gpu/ipc/in_process_command_buffer.h

Index: gpu/ipc/in_process_command_buffer.h
diff --git a/gpu/ipc/in_process_command_buffer.h b/gpu/ipc/in_process_command_buffer.h
index ac4ef0238789e68f2f57d017adcac7823fe738ad..84f7030b73b6b7c6cc03efb7c551930979e2f334 100644
--- a/gpu/ipc/in_process_command_buffer.h
+++ b/gpu/ipc/in_process_command_buffer.h
@@ -129,6 +129,8 @@ class GPU_EXPORT InProcessCommandBuffer : public CommandBuffer,
   void SignalSyncToken(const SyncToken& sync_token,
                        const base::Closure& callback) override;
   bool CanWaitUnverifiedSyncToken(const SyncToken* sync_token) override;
+  int32_t CreateFence(ClientFence fence) override;
+  void DestroyFence(int32_t id) override;
 
   // The serializer interface to the GPU service (i.e. thread).
   class Service {